HD6417660 RENESAS [Renesas Technology Corp], HD6417660 Datasheet - Page 116

• Manufacturer Part Number: HD6417660
• Description: Renesas 32-Bit RISC Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

Repeat Start Register (RS): RS holds the start address of the repeat loop that is controlled by the
zero overhead repeat control function. This register can be accessed in DSP mode. At reset, the
initial value of this register is undefined. This register is not affected in the exception handling
state.
Repeat End Register (RE): RE holds the address for detecting the execution of the end
instruction of repeat loop that is controlled by the zero overhead repeat control function.
This register can be accessed in DSP mode. At reset, this register is initialized to 0. This register
is not affected in the exception handling state.
Modulo Register (MOD): MOD stores the modulo end address and modulo start address for
modulo addressing in upper and lower 16 bits. The upper and lower 16 bits of the MOD register
are referred to as the ME register and MS register, respectively. This register can be accessed in
DSP mode. At reset, the initial value of this register is undefined. This register is not affected in
the exception handling state.
The above registers can be accessed by the control register load instruction (LDC) and store
instruction (STC). Note that the LDC and STC instructions for the RS, RE, and MOD registers
can be used only in privileged DSP mode and user DSP mode. The LDC and STC instruction for
the SR register can be executed only when the MD bit is set to 1 or in user DSP mode. Note,
however, that the LDC and STC instructions can modify only the RC11 to RC0, RF1 to RF0,
DMX, and DMY bits in the SR, as described below.
• In user mode, if the LCD and STC instructions are used for the SR, an illegal instruction
• In privileged and privileged DSP modes, all SR bits can be modified.
• In user DSP mode, the SR can be read by the STC instruction.
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exception occurs.
In user DSP mode, the LDC instruction can be issued to the SR but only the DSP extension
bits can be modified.